Reduction dubbing and recording of sound on film



June 19, 1934.

`s. c. WHITMAN REDUCTION DUBBING AND RECORDING OF SOUND ON FILM Filed Oct. 22, 1932 lllllllllllllllll Il IN V EN TOR.

f M W ATTORNEYS.

Patented June 19, 1934 REDUCTION DUBBING AND RECORDING OF SOUND ON FILM Stewart C. Whitman, New York, N. Y.

Application October 22, 1932, Serial No. 639,144

7 Claims.

' This invention relates to new and useful improvements in the art of recording sound on iilm and more particularly to apparatus for re-recording sound from large film onto small film.

An object of the invention is to provide a continuous reduction printing apparatus for recording sound on 16 millimeter film,

Another object of the invention is to provide printing means whereby sound on 35 millimeter 10 film may be transferred to 16 millimeter film.

\A further object of the invention is to provide reduction printing apparatus for 16 millimeter film by theuse of which all the sound frequencies are preserved in the reduced record.

With these and other objects in view, my invention consists in the novel features of construction, combination, and arrangement of parts as will be hereinafter referred to 4and more particularly pointed out in the specification and claims.

In the drawing, forming a part of this application:

Figure 1 is a vertical longitudinal section through my apparatus.

Figures 2 and 3 are vertical longitudinal sec- 25 tions of a modification of my device.

The various arrangements of the above elements will be more particularly described in the following disclosure.

Considerable experimentation has been carried f out in attempts to successfully record sound on 16 millimeter iilm either by direct recording or by transferring from millimeter film. 'Ihese efforts have generally met with failure due .to an inherent characteristic of the film emulsion. The

35 allowable space for photographing sound impulses on 16 millimeter film is so small that the sound images to be photographed approach in size the dimensions Vof the emulsion granules themselves. Asa result the recording light instead of producing clean, sharp images on the film, reduces completely great number of granules which lie only partially in the exposed region. This results in sound images whose boundaries instead of being sharp are jagged and bumpy. At

high sound frequencies where the photographic images are extremely close together a portion of these undesired peaks and bumps overlap, thereby ruining the sound record. It was hoped that this condition could be alleviated by transferring the sound from 35 millimeter film using reduction printing. It was discovered however that the same fault existed on the 35 millimeter film to some extent and when the sound images and the spaces between them were sufficiently reduced optically the resulting record was hopelessly blurred.

The present invention describes a method of accomplishing this reduction process which has yielded exceptionally fine results in practice.

If the sound track on 35 millimeter film is examined under the microscope the protruding exposed granules which destroy the sharpness of the sound images can be clearly seen. However, if the sound track is magnified and the sound images thrown on the screen, it is noted that the sharply outlined irregularities have become blurred and the sound image boundaries appear as straight lines surrounded by smooth, hazy nebulae. This optical phenomenon is utilized in the present invention. The 35 millimeter sound track is greatly enlarged and the reduction printing on the 16 -millimeter film is carried out directly from this enlargement. The resulting record on the 16 millimeter lm retains all the original sound frequency images as separate entities. The nebulae noted in the enlargement overlap on the reduction print to result in a gray, matt background. This gray background reduces the contrast to some extent and raises the ground noise level upon reproduction. This condition, however, can be compensated for either by a judicious selection of sound take-off apparatus and amplifier, or, by transferring the record again and increasing contrast by known photographlc and developing methods.

A still further improved method of reduction recording can be used if a wide sound trackis used in connection with 16 millimeter film having sprocket holes only on one side. If the irregular sound images on the film are magnified only in a transverse direction with respect to the sound track, it can be seen that the irregular boundaries approach straight lines as the magnification in that direction increases. Therefore, if, in the enlarging process, the track is mag- -nified to a greater extent transversely, than it is longitudinally substantial improvement is noted upon subsequent reduction. This astigmatic enlargement can only be used, of course, in cases where the nal sound track can be -abnormally wide. Such enlargement can be accomplished for example by grinding the lens so that the curvature is greater along one diameter than it is along another diameter perpendicular to the first, and the magnification is proportionately distorted.

The apparatus and method employed may be more clearly understood by referring to the drawing. Figure l shows a preferred form of my device wherein the numeral 1 denotes -a box-like chamber containing the 35 millimeter film reels 2 and 3, and the light gate 4, past which the film 3a is caused to travel by driving means not shown. A powerful source of illumination 5 is provided in the housing 6. This light source may be either a carbon arc or incandescent projection lamp. The lens 7 focusses the beam upon the film sound track through the light gate 4. The transmitted light is picked up by the enlarging lens system 8 enclosed in the tube 9 and throws a magnified image of the sound track upon the opal glass screen 10 which is mounted in the enclosed chamber 11. This magnified image is directly reduced to the proper size by the lens system 12 mounted in theetube 13 and the reduced image photographed upon the 16 millimeter film, shown at 14, through the gate 15. The camera box 16 is similar to box 1 and contains means for driving the film from reel 17 past the light gate 15 and the guide 15a and rewinding the exposed iilm on reel 18. The entire apparatus is light-proof and the inner surfaces blackened. It will be noted that using this apparatus automatic synchronization is achieved, it being only necessary to--run the two lms at rated speeds, respectively. This apparatus will accomplish the results heretofore outlined.

Figures 2 and 3 show a modified form of the invention whereby a single printer may be 'used both for enlargement and reduction by merely changing the lenses. Similar reference characters designate corresponding parts in the two figures. In Figure 2 ,the light source 19, shown here as an incandescent lamp with a reflector 20 is provided in a lamp housing 21. The light is focussed on the sound track of the 35 millimeter lm 22 through the gate 23 by means of the condenser lens 24. The arrangement of the box 25 and the reels 26 and 27 is similar to those-in Figure 1. lThe camera box 28 contains the reels 29 and 30 carrying the 35 millimeter film 31. Driving means, not shown, carry the film past the light gate 32 and the guide 33. The light passing through the gate 23 is picked up by the enlarging lens system 34 contained in the tube 35 and the enlarged image photographed on the film 31. Figure 3 is identical with Figure 2 except that the lens system 34 is replaced by a reducing lens system 36, the condenser lens 24 is replaced by the lens 37 and the gates 23 and 32 are properly adjusted. The film 31 carrying the enlarged sound track is placed in the chamber 25, and the 16 millimeter film 38 is placed on reels 39 and 40 in the chamber 28. The enlarged record is reduced by the lens system 36 to the proper size and photographed on the 16 millimeter film 38. Since this method is non-synchronous, a careful record of footage must be kept and the final recording speed for the 16 millimeter film calculated therefrom.

While I have described above preferred adaptations of my invention, I do not desire to be limited to minor details of construction but wish to claim broadly the principle of reduction recording involving a previous enlargement of the record.

Having thus described the invention what is claimed is: f

1. A unitary apparatus for transferring sound records from large to smaller film comprising a projection chamber, a camera box, a light-proof chamber communicating therebetween and provided with a central enlargement, a translucent screen carried in the enlargement of said last mentioned chamber, a magnifying optical system in said light-proof chamber intermediate of said screen and projection chamber, and a reducing optical system also carried in said light-proof chamber interposed between said screen and camera box.

2. A unitary apparatus for transferring sound records from large to smaller film, comprising a projection chamber adapted to contain the large lm, a camera box adapted to contain the smaller film, a light-proof chamber communicating with said film chambers, said last mentioned communicating chamber being centrally enlarged, a translucent screen carried in the central enlargement of said communicating chamber, an enlarging lens system interposed in the communicating chamber between said screen and projection chamber, a reduction lens system interposed in said communicating chamber between said screen and said camera box and a light source in association with the projection chamber, said chambers and camera box with elements carried therein forming a unitary structure.

3. In an apparatus of the class described, a projection chamber adapted to receive large film, a recording chamber adapted to receive smaller film, said chambers being of substantially the same size and shape and being spaced one from the other, a light-proof communicating chamber having connection and communication with said projection and recording chambers, said communicating chamber being of reduced diameter and provided with an intermediate enlarged portion, a translucent screen removably supported in the enlarged portion of said communicating chamber, an enlarging lens system carried in said communicating chamber and interposed between said screen and said projection chamber, a reduction lens system contained in the communicating chamber and interposed-between said screen and said recording chamber, a light source in communication with said projection chamber, said chambers forming a unitary structure as and for the purposes described.

4. In a system for. transferring sound records from one film to another film, a projection chamber, a camera box, a light-proof chamber communicating therebetween, a translucent screen mounted transverselyn in said communicating chamber, a magnifying optical system mounted in said communicating chamber between said projection chamber and said screen, and a reducing optical system mounted in said communicating chamber between said screen and said camera box, said magnifying optical system being con-.I

structed to produce on said screen an image enlarged substantially more in one direction than in the direction perpendicular thereto, said lightproof communicating chamber forming a unitary structure with said projection chamber and said camera box and forming a light-proof path between the light gates in said projection chamber and said camera box.

5. In a system for transferring sound records from one film to another film, a projection chamber, a camera box, a light-proof chamber communicating therebetween, a translucent screen mounted in said communicating chamber between the light-gates in said projection chamber and said camera box and substantially perpen-.'

dicular to the direct path between said lightgates, a magnifying optical system mounted in said communicating chamber between said pro- .jection chamber and said screen. and a reducing optical system mounted in-said communicating chamber between said screen and said camera box, said magnifying optical system being constructed to produce on said screen an image enlarged substantially more in one direction than in the direction perpendicular thereto, said lightproof communicating chamber forming al unitary structure with said projection chamber and said camera box and forming a light-proof path between the light-gates in said projection chamber and said camera box.

6. In a system for transferring sound records from one lm to another lm, a projection chamber, a camera box, a light-prooi chamber communicating therebetween and having a transversely enlarged portion between said projection chamber and said camera box, a translucent screen mounted in said enlarged portion of said communicating chamber between the light-gates in said projection chamber and said camera box and substantially perpendicular to the direct path between said light gates, a magnifying optical system mounted in said communicating chamber,

gates in said projection chamber and said camera box. Y

7. In a system for transferring sound records from one iilm to another iilm, a projection chamber, a camera box, a light-proof chamber communicating therebetween and having a transversely enlarged portion between said projection chamber and said camera box, a translucent screen mounted in said enlarged portion of said communicating chamber between the light-gates in said projection chamber and said camera box and substantially perpendicular to the direct path between said light-gates, a magnifying optical system mounted in said communicating chamber between said projection chamberV and said screen, and a reducing optical system mounted in said communicating chamberbetween said screen and said camera box, said magnifying optical system being constructed to produce on said screen an image enlarged substantially more in'one direction than in the direction perpendicular thereto, said light-prooi communicating chamber forming a unitary structure with said projection chamber and said camera box and forming a light-proof path between the lightgates in said projection chamber and said camera lbox.

STEWART C. WHITMAN. 

